In recent years, portable electronic devices such as IC cards with a built-in IC (Integrated Circuit) chip have been commonly used. Systems that use a conventional portable electronic device authenticate the legitimacy of the owner of the portable electronic device by using secret authentication information such as a PIN (Personal Identification Number).
However, if the PIN is leaked (divulged), there is the possibility of unauthorized use of the system by a third party who disguises itself as the owner of the portable electronic device, and the security of the system may be degraded.